Dr. Robbins participates in the NCI project studying the thyroid effects of the nuclear power reactor accident in Chernobyl. The case-control study on children in Belarus who developed thyroid cancer has been published in Radiation Research, and demonstrated a clear relationship between the estimated thyroid radiation dose from I-131 and the cancers. The prospective study of cohorts of children in Belarus and Ukraine is now proceeding in both countries and screening is under way in Minsk, Gomel and Kiev. Two biennial screening cycles have been completed and the prevalence of thyroid nodular disease in the first cycle is now being analyzed. Reconstruction of the thyroid radiation dose is proceeding in parallel. The end points include thyroid neoplasia, both benign and malignant, thyroid autoimmune disease, and hyperparathyroidism. A workshop on the potential effect of iodine deficiency on thyroid cancer risk was held and was published in Thyroid. The design and methods of the cohort study have been published in Radiation Research.